Which of the following is NOT a CNS effect of ketamine?

Which of the following is NOT a CNS effect of ketamine?

• A. Analgesia
• B. Nystagmus
• C. Lowers seizure threshold
• D. Decreases intracranial pressure

Answer: (D)

Ketamine’s CNS actions are mostly excitatory in nature and include analgesia and dissociation, not depression. Analgesia is produced because NMDA receptor blockade dampens central sensitization to pain. Nystagmus is a common CNS effect linked to the drug’s effects on brainstem and oculomotor function during induction and dissociation. What about intracranial pressure? Ketamine tends to increase cerebral blood flow and cerebral metabolic activity, which can raise intracranial pressure, particularly in patients with compromised autoregulation or brain injury. So decreasing intracranial pressure goes against ketamine’s typical CNS effects. Some patients may experience changes in seizure threshold with ketamine, reflecting its complex impact on neuronal excitability in susceptible individuals, but the standout point here is that lowering intracranial pressure is not an expected CNS effect of ketamine.

Ketamine’s CNS actions are mostly excitatory in nature and include analgesia and dissociation, not depression. Analgesia is produced because NMDA receptor blockade dampens central sensitization to pain. Nystagmus is a common CNS effect linked to the drug’s effects on brainstem and oculomotor function during induction and dissociation.

What about intracranial pressure? Ketamine tends to increase cerebral blood flow and cerebral metabolic activity, which can raise intracranial pressure, particularly in patients with compromised autoregulation or brain injury. So decreasing intracranial pressure goes against ketamine’s typical CNS effects.

Some patients may experience changes in seizure threshold with ketamine, reflecting its complex impact on neuronal excitability in susceptible individuals, but the standout point here is that lowering intracranial pressure is not an expected CNS effect of ketamine.